Kinetics, isotope effects, and mechanism of the hydrogenation of carbon monoxide on supported palladium catalyst

Journal Article · Thu Sep 15 04:00:00 EDT 1983 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100242a016· OSTI ID:5597090

Mori, T ^[1]; Masuda, H; Imai, H; Miyamoto, A; Hasebe, R; Murakami, Y

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1. Government Industrial Research Inst., Nagoya, Japan

Kinetics and isotope effects for the C-O bond dissociation in the hydrogenation of CO on palladium/alumina (Pd/Al/sub 2/O/sub 3/) catalyst were investigated by using pulse surface reaction rate analysis (PSRA). The rate-determining step was found to be the C-O bond dissociation of the adsorbed CO species. The rate constant for the C-O bond dissociation process per adsorbed CO molecule was determined at various temperatures and Arrhenius parameters of the rate constant were obtained. The rate constant in flowing deuterium (D/sub 2/)(k/sub D/) was considerably larger than that in flowing H/sub 2/(k/sub H/), indicating an inverse isotope effect. The average value of k/sub H//k/sub D/ was 0.61. The extent of the inverse isotope effect for Pd was more significant than that for nickel (Ni)(k/sub H//k/sub D/ = 0.75). The preexponential factor for k/sub H/ on Pd (1.6 x 10/sup 4/s/sup -1/) was much smaller than that on Ni (5.4 x 10/sup 6/s/sup -1/). It was concluded that adsorbed CO is not directly dissociated to surface carbon and oxygen atoms but hydrogen atoms play an important role in the C-O bond dissociation. Further details of the mechanism for the C-O bond dissociation were discussed from the observed kinetics and isotope effects. 5 figures.

• OSTI ID: 5597090
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 87:19; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

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ADSORPTION
ALKANES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
DATA
DEUTERIUM
DISSOCIATION
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
GASES
HIGH TEMPERATURE
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFORMATION
INFRARED SPECTRA
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LIGHT NUCLEI
METALS
METHANATION
METHANE
NICKEL
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PALLADIUM
PLATINUM METALS
PRODUCTION
REACTION KINETICS
SAMPLE PREPARATION
SORPTION
SORPTIVE PROPERTIES
SPECTRA
STABLE ISOTOPES
SURFACE PROPERTIES
SYNTHESIS GAS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRANSITION ELEMENTS
WATER